We had a smooth flight.

我们的飞机飞得很平稳。

《新英汉大辞典》

I hope you'll have a smooth flight.

我希望你飞行顺利。

youdao

Me, neither. I hope it's a smooth flight.

我也是。我希望这是趟平顺的飞行。

youdao

The engine constantly throttles up and down, not only to counter the drag on the satellite from residual air molecules in near space but also to smooth the flight of the vehicle to minimise the noise in the gravity measurements.

BBC: Goce gravity mapper surfs atmosphere

Your flight has been smooth, the food good, the flight attendants smiling and the seats comfortable.

BBC: Stopover in Abu Dhabi

The early part of the flight was smooth.

BBC: The other pilot